Title page for ETD etd-05202011-111953

Type of Document Dissertation
Author Marinovici, Laurentiu Dan
URN etd-05202011-111953
Title Communication-constrained Feedback Stability and Multi-agent System Consensusability in Networked Control Systems
Degree Doctor of Philosophy (Ph.D.)
Department Electrical & Computer Engineering
Advisory Committee
Advisor Name Title
Zhou, Kemin Committee Chair
Gu, Guoxiang Committee Co-Chair
Wei, Shuangqing Committee Member
Wolenski, Peter Committee Member
Sathivel, Subramanian Dean's Representative
  • communication constrained feedback
  • multi-agent systems
  • consensusability
  • logarithmic quantizer
  • networked control systems
Date of Defense 2011-05-12
Availability unrestricted
With the advances in wireless communication, the topic of Networked Control Systems

(NCSs) has become an interesting research subject. Moreover, the advantages they offer

convinced companies to implement and use data networks for remote industrial control and

process automation. Data networks prove to be very efficient for controlling distributed

systems, which would otherwise require complex wiring connections on large or inaccessible areas. In addition, they are easier to maintain and more cost efficient. Unfortunately,

stability and performance control is always going to be affected by network and communication issues, such as band-limited channels, quantization errors, sampling, delays, packet

dropouts or system architecture.

The first part of this research aims to study the effects of both input and output quantization on an NCS. Both input and output quantization errors are going to be modeled as sector bounded multiplicative uncertainties, the main goal being the minimization of the quantization density, while maintaining feedback stability. Modeling quantization errors as uncertainties allows for robust optimal control strategies to be applied in order to study the accepted uncertainty levels, which are directly related to the quantization levels. A new feedback law is proposed that will improve closed-loop system stability by increasing the upper bound of allowed uncertainty, and thus allowing the use of a coarser quantizer.

Another aspect of NCS deals with coordination of the independent agents within a Multi-agent System (MAS). This research addresses the consensus problem for a set of discrete-time agents communicating through a network with directed information flow. It examines the combined effect of agent dynamics and network topology on agents' consensusability. Given a particular consensus protocol, a sufficient condition is given for agents to be consensusable. This condition requires the eigenvalues of the digraph modeling the

network topology to be outer bounded by a fan-shaped area determined by the Mahler

measure of the agents' dynamics matrix.

  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  marinovicidiss.pdf 1.38 Mb 00:06:22 00:03:16 00:02:52 00:01:26 00:00:07

Browse All Available ETDs by ( Author | Department )

If you have questions or technical problems, please Contact LSU-ETD Support.